1. Field of Invention
The present invention relates to an optical interconnection module. More particularly, the present invention relates to an optical interconnection module capable of quickly aligning and improving the optical coupling efficiency.
2. Related Art
Along with the progress in optical communication element technology, the system develops toward having broadband and high speed, and the packaging technology must meet the requirements of light, thin, short and small, easy packaging, low cost and high reliability. Due to the development of the Internet, people's demand on the bandwidth of the network is continuously increased, and the optical network gradually develops toward having a large volume, lots of variations, high reliability, and being economical and effective. The optical communication is no longer limited to the remote communication. From the backbone network, metropolitan area network, access network, the optical networking is realized step by step, and the fiber to home is gradually formed. In order to achieve the high speed and popularization of the optical communication, it is necessary to set up an optoelectronic packaging technology of low cost, so as to develop low cost optical communication elements and high speed transceiver modules, which is the focus of the progressing optical interconnection technology. Since the Internet completely adopts optical fiber transmission, the signal transmission in the future high performance computer develops toward parallel optical interconnect. An optical method is used to connect the computer chip, module, circuit board, base plate, case and processor, so as to transmit a signal in the manner of high speed photon, thus solving the bottleneck problems in the conventional electronic transmission, such as heat, speed, limited bandwidth. Along with the rise of the processing speed of CPU or other chips in a computer, the requirement of using optical communication to transmit data is gradually increased. It is foreseeable that when the computer is integrated with the optical communication technology, the optical interconnect and optical data communication may bring great impacts on the industry and technology.
Therefore, in a technology relative to the optical interconnection, for example, U.S. Pat. No. 7,058,247, an index matching layer is disposed on one side of an optical interconnect module facing a circuit board. The alignment mechanism has the following options: one is disposing a bump on the index matching layer and an opening at the position corresponding to the circuit board, which is used for alignment when the optical interconnect module is assembled on the circuit board; or, an opening is disposed in the index matching layer, and a bump is disposed on the circuit board; or, an opening penetrating the electrode portion of the optical interconnect module is disposed in the index matching layer, a solder ball is embedded in the circuit board, and by inserting the solder ball into the opening to contact the electrode, the optical interconnect module and the circuit board can be fixed by welding. However, in the U.S. Pat. No. 7,058,247, an index matching layer is added into the optical interconnect module, and thus an additional process is needed.
Further, in U.S. Pat. No. 6,599,031, as for the configuration, an optical receiver and an optical transmitter are disposed in a depressed portion of the package; next, a layer of transparent polymer is covered on the depressed portion for sealing and light transmission; and then, microlens arrays are formed on the transparent polymer. Similarly, a depressed portion is formed in the optoelectronic substrate, a layer of transparent polymer is filled into the depressed portion, and microlens arrays corresponding to those of the package are connected onto the polymer. As the surface of the polymer must be polished before connecting the microlens arrays, the process is complicated, and it is difficult to integrate the polymer with the package and optoelectronic substrate. Moreover, as the lenses are independently fabricated on the package and the optoelectronic substrate, the fabricating cost is high.
Further, in U.S. Pat. No. 6,512,861, the alignment is fulfilled in two steps. Firstly, two alignment balls are disposed on one side of a chip of ball grid array (BGA) package, and V-grooves are disposed in the circuit board corresponding to the alignment balls. The alignment balls are engaged with the V-grooves to approximately align the chip and the circuit board, such that an optical transceiving element disposed on the chip can be coupled to an optical waveguide of the circuit board. Next, the solder ball disposed on one side of the chip is directly aligned with the pad area on the circuit board, thus fulfilling the alignment and position. Therefore, in the U.S. Pat. No. 6,512,861, as for the first alignment mechanism, the alignment balls and V-grooves must be re-arranged, and thus, an additional process is needed. Finally, the solder ball is positioned in the pad area to fulfill the alignment and fixing. However, as the processing accuracy of welding the solder ball to the pad area is not high, slight shift may occur, thus affecting the accuracy of the alignment.